Revealing the distinct clinical patterns and relapse risk factors in seronegative IgG4-RD patients: A retrospective cohort study over a decade.

OBJECTIVES: Our study aimed to investigate the distinct clinical patterns of seronegative IgG4-related disease (IgG4-RD) patients. METHODS: We retrospectively enrolled 698 treatment-naïve IgG4-RD patients in this study. Patients were divided into four different subgroups according to their baseline serum IgG4 levels. The distinct clinical patterns of seronegative IgG4-RD patients were revealed through the comparison of baseline clinical data and disease prognosis among the different subgroups. COX regression analyses were used to investigate the risk factors for disease relapse and to construct the nomogram model. RESULTS: Seronegative IgG4-RD patients account for a minority of IgG4-RD patients (49/698, 7.02%). The proportions of seronegative IgG-RD patients in our study and several Asian cohorts were significantly lower than those of the European and American cohorts. Seronegative IgG4-RD patients got lower serum IgG levels (p < 0.0001), lower eosinophil count (p < 0.0001), lower serum IgE levels (p < 0.0001)), lower IgG4-RD responder index (RI) scores (p < 0.0001), and fewer affected organ numbers (p < 0.0001) compared with other subgroups, whereas they were more likely to manifest fibrotic type with some special organ involvement. Younger age at onset, GCs monotherapy, elevated C-reactive protein level, and elevated erythrocyte sedimentation rate level are the risk factors for the disease relapse of seronegative IgG4-RD patients. An effective nomogram model predicting disease relapse of seronegative IgG4-RD patients was constructed. Seronegative IgG4-RD patients with scores >84.65 at baseline were susceptible to suffering from disease relapse. CONCLUSIONS: Distinct clinical features and multiple risk factors for disease relapse of seronegative IgG4-RD patients have been revealed in this study. A nomogram model was constructed to effectively predict disease relapse during the follow-up period.

Withdrawal of immunosuppressants and low-dose steroids in patients with stable IgG4-RD (WInS IgG4-RD): an investigator-initiated, multicentre, open-label, randomised controlled trial.

OBJECTIVES: IgG4-related disease (IgG4-RD) is an immune-mediated, fibroinflammatory disease. Induction treatment with glucocorticoid (GC) is usually effective, but its tendency of relapse makes the strategy for maintenance treatment a challenge. The WInS IgG4-RD (withdraw immunosuppressants (IMs) and steroid in stable IgG4-RD) trial tested whether discontinuation of GC and IM was feasible in stable IgG4-RD. METHODS: The WInS IgG4-RD trial was a multicentre, open-label, randomised controlled trial. Patients with IgG4-RD receiving GC+IM as maintenance treatment with clinically quiescent disease for at least 12 months were randomised (1:1:1) into three groups: group 1: withdraw GC+IM; group 2: withdraw GC but maintain IM; group 3: maintain GC+IM. The primary outcome was the relapse rate of disease within 18 months. The secondary outcomes included the changes of IgG4-RD Responder Index (RI), Physician's Global Assessment (PGA), serum IgG4 and IgG, as well as adverse events. RESULTS: One hundred and forty-six patients were randomised, with 48 patients in group 1, 49 patients in group 2 and group 3, respectively. Within the 18-month follow-up period, disease relapse occurred in 25 out of 48 (52.1%) patients in group 1 vs 7 out of 49 (14.2%) in group 2 and 6 out of 49 (12.2%) in group 3 (p<0.001). The changes in RI and PGA were significantly higher in group 1 than in group 2 (p<0.001) or group 3 (p<0.001). CONCLUSIONS: The maintenance of IMs, with or without low-dose GC, was found to be superior to withdraw GC+IM in preventing relapse for long-time stable IgG4-RD. TRIAL REGISTRATION NUMBER: NCT04124861.

Expansion and surface makers of age-associated B cells in IgG4-related disease.

OBJECTIVES: To assess the expression of age-associated B cells (ABCs), and characterise the surface markers of ABCs in patients with IgG4-related disease (IgG4-RD). METHODS: Fifty-one newly diagnosed patients with IgG4-RD, 18 IgG4-RD patients with disease remission, 34 patients with other autoimmune diseases, and 61 age- and sex-matched healthy controls (HCs) were included. Circulating ABCs, as well as surface markers were detected by flow cytometry, and tissue infiltration of ABCs were assessed by immunofluorescence (IF). The expression of ABCs in the affected organs of LatY136F knock-in (LAT) mouse models (IgG4-RD mouse model) were explored by flow cytometry and IF. RESULTS: The percentages and absolute numbers of ABCs (gated as CD21-T-bet+CD11c+) in CD19+ B cells raised remarkably in untreated IgG4-RD patients than HC, and reduced significantly after treatment. The percentage of CD27+ABCs, DN2 B cells and activated naive B cells was higher in patients with IgG4-RD than in HCs and patients with multiple autoimmune diseases, whereas the percentage was comparable with that in patients with systemic lupus erythematosus. Phenotypical analysis revealed upregulated levels of CD86, TACI, CD38, and downregulated level of CXCR3 in peripheral CD19+CD21-CD11c+ B cells of IgG4-RD patients compared with that of HC. In IgG4-RD patients, CD19+CD21- CD11c+ cells expressed higher levels of CD80, CXCR3, TACI, CD95, and BAFF-R, while lower levels of CD86, CD27, CD38, and CXCR5 compared with CD19+ CD21- CD11c- B cells. ABCs (CD11c+T-bet+ gated in B220+ cells) were increased significantly in lungs of LAT mice than that of wild type (WT) mice. CONCLUSIONS: ABCs were expanded both in the peripheral blood and affected tissues of patients with IgG4-RD as well as in the lungs of LAT mice, indicating the potential roles of ABCs in IgG4-RD pathogenesis.

Comparison of clinical characteristics between patients with axial spondyloarthritis with and without acute anterior uveitis: a multicentre study of the Chinese Spondyloarthritis Registry.

OBJECTIVES: This study explores the clinical characteristics associated with the occurrence of acute anterior uveitis (AAU) in patients with axial spondyloarthritis (axSpA) within a large, multicentre database. METHODS: This observational, cross-sectional study of patients with axSpA used data from the Chinese Spondyloarthritis Registry between August 1, 2018, and March 31, 2020. The demographic and clinical features of patients with and without AAU were compared. Univariate and multivariate analyses were performed to determine the association between variables and uveitis. RESULTS: A total of 4304 patients were included in this study. The prevalence of AAU in patients with axSpA was 10.59%. Multivariate logistic regression analysis revealed a positive correlation between AAU and age at diagnosis (odds ratio [OR], 1.026; p<0.001), disease duration (OR, 2.117; p<0.001), current or past Achilles tendinitis (OR, 1.692; p<0.001), current or past dactylitis (OR, 1.687; p=0.002), current or past psoriasis (OR, 3.932; p<0.001), presence of human leukocyte antigen-B27 (HLA-B27) (OR, 2.787; p<0.001), and a good response to non-steroidal anti-inflammatory drugs (NSAIDs) (OR, 1.343; p=0.027). CONCLUSIONS: AAU was the most common extra-articular manifestation in the Chinese Spondyloarthritis Registry. In Chinese patients with axSpA, older age at diagnosis, longer disease duration, presence of HLA-B27, current or past Achilles tendinitis, current or past dactylitis, current or past psoriasis, and a good response to NSAIDs were positively associated with AAU.

mTORC1-GLUT1-mediated glucose metabolism drives hyperactivation of B cells in primary Sjogren's syndrome.

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease characterized by B cell hyperactivation and hypergrammaglobulinemia. Currently, the role of metabolic pathways in the B cells of pSS patients is poorly defined. Here, we showed that upon cytosine phosphate-guanine (CpG)/sCD40L/IL-4 stimulation, B cells proportionally increased glycolysis and oxygen consumption, and compared with B cells from healthy controls (HCs), B cells from pSS patients exhibited higher glycolysis capacity and maximal oxidative respiration (OXPHOS). We also found that glucose transporter 1 (GLUT1) expression in B cells from pSS patients was significantly higher than that in B cells from HCs. Treatment with 2-deoxy-d-glucose (2-DG) inhibited the activation of B cells in pSS patients. Both 2-DG and Metformin inhibited the proliferation, formation of plasma/plasmablasts and decreased the IgG and IgM levels in the supernatants of B cells from pSS patients. Furthermore, inhibition of mTORC1 by rapamycin had an effect similar to that of 2-DG, suppressing B cell activation, proliferation and antibody production. Taken together, we demonstrated that B cells from pSS patients are more metabolically active than those from HCs and suggested that the mTORC1-GLUT1 glycolysis pathways were the major drivers of B cell hyperactivation and autoantibody production in pSS patients.

Memory CD4+T cell profile is associated with unfavorable prognosis in IgG4-related disease: Risk stratification by machine-learning.

IgG4-related disease (IgG4-RD) is a chronic immune-mediated disease with heterogeneity. In this study, we used machine-learning approaches to characterize the immune cell profiles and to identify the heterogeneity of IgG4-RD. The XGBoost model discriminated IgG4-RD from HCs with an area under the receiver operating characteristic curve of 0.963 in the testing set. There were two clusters of IgG4-RD by k-means clustering of immunological profiles. Cluster 1 featured higher proportions of memory CD4+T cell and were at higher risk of unfavorable prognosis in the follow-up, while cluster 2 featured higher proportions of naïve CD4+T cell. In the multivariate logistic regression, cluster 2 was shown to be a protective factor (OR 0.30, 95% CI 0.10-0.91, P = 0.011). Therefore, peripheral immunophenotyping might potentially stratify patients with IgG4-RD and predict those patients with a higher risk of relapse at early time.

Methylprednisolone pulse therapy promotes the differentiation of regulatory T cells by inducing the apoptosis of CD4+ T cells in patients with systemic lupus erythematosus.

OBJECTIVES: To investigate the differentiation of regulatory T cells (Tregs) induced by methylprednisolone (MP) pulse therapy in patients with Systemic Lupus Erythematosus (SLE). METHODS: We enrolled 30 patients with SLE and analyzed peripheral blood mononuclear cells (PBMCs) before and after MP pulse therapy. Peripheral Tregs, apoptosis of PBMCs subsets, and TGFß production by monocytes was quantified by flow cytometry. Proliferation and IFN-γ production of CD4+ T cells were measured. Furthermore, TGFß1 production by human monocyte-derived macrophages (HMDM) stimulated with MP-treated CD4+ T cells were quantified by ELISA. RESULTS: Peripheral Tregs was significantly increased after MP pulse therapy (6.76 ± 1.46% vs. 3.82 ± 1.02%, p < 0.01), with an expansion of Nrp1- induced Tregs (4.54 ± 0.46% vs. 1.75 ± 0.38%, p < 0.01). Proliferation and IFN-γ production of CD4+ T cells were significantly decreased after MP pulse therapy. MP pulse therapy induced CD4+ T cell apoptosis (early apoptosis, 26.34 ± 3.54% vs. 14.81 ± 2.89%, p < 0.01) and TGFß expression on monocytes (6.02% vs. 2.45%, p < 0.01). Furthermore, MP induced CD4+ T cell apoptosis in vitro, which stimulated HMDM to produce TGFß. Moreover, elevated TGFß level in supernatant from HMDM stimulated with MP-treated CD4+ T cells promoted Tregs differentiation. CONCLUSIONS: MP pulse therapy induces CD4+ T cell apoptosis, which promotes monocytes to produce TGFß and further facilitates Tregs differentiation. Newly-differentiated Tregs suppress proliferation and IFN-γ production of CD4+ T cells and contribute to immunoregulatory milieu after MP pulse therapy.

Prediction of new organ onset in recurrent immunoglobulin G4-related disease during 10 years of follow-up.

OBJECTIVE: Frequent relapse is a prominent challenge in managing immunoglobulin G4-related disease (IgG4-RD). According to the types of organs involved in relapse, relapse patterns were divided into recurrent organ involvement (ROI) and new organ involvement (NOI). We aimed to investigate the discrepancy in clinical relapse patterns and establish an effective prognostic nomogram for NOI. METHODS: We retrospectively enrolled 125 IgG4-RD patients who experienced relapse during the follow-up period. Patients were classified into two groups: those with NOI (including NOI and NOI + ROI) and without NOI (ROI). Logistic regression analyses were used to assess the risk factors for NOI. The results were externally validated by a separate prospective cohort of 39 patients with relapse. RESULTS: There were 81 (64.8%) and 44 (35.2%) patients without NOI and with NOI, respectively. Patients without NOI showed higher baseline disease activity. The most common ROIs were the lacrimal gland and submandibular gland, while the lung and urinary system were the most involved in NOI. Re-elevation of serum IgG4 level to 74.31% of baseline was associated with NOI. Multiple relapses, organ involvement type at baseline, glucocorticoids combined with immunosuppressive drugs (IM) or IM alone during the maintenance period, and relapse IgG4/baseline IgG4 ratio were included in the nomogram. Both internal and external validations showed good agreement and discrimination. CONCLUSIONS: About one third of IgG4-RD patients with relapse suffer from NOI. We developed a risk stratification model that can effectively predict the future risk of NOI. Glucocorticoid and IM combined therapy during maintenance is also recommended.

TSLP promoting B cell proliferation and polarizing follicular helper T cell as a therapeutic target in IgG4-related disease.

OBJECTIVE: To figure out the functions of thymic stromal lymphopoietin (TSLP) in IgG4-related disease (IgG4-RD). METHODS: Plasma TSLP levels were tested by Elisa, and its receptors were detected by flow cytometry. Expressions of TSLP and TSLPR in involved tissues were stained by immunohistochemistry and immunofluorescence. Proliferation, apoptosis, and B subsets of TSLP stimulated-B cells were analyzed by flow cytometry. TSLP-stimulated B cells were co-cultured with CD4+ Naïve T cells. Signaling pathway was identified by RNA-sequencing and western blot. Anti-TSLP therapy was adapted in LatY136F knock-in mice (Lat, IgG4-RD mouse model). RESULTS: Plasma TSLP level was increased in IgG4-RD patients and was positively correlated with serum IgG4 level and responder index (RI). TSLPR was co-localized with CD19+ B cells in the submandibular glands (SMGs) of IgG4-RD. TSLP promoted B cell proliferation, and TSLP-activated B cells polarized CD4+ naive T cells into follicular helper T (Tfh) cells through OX40L. RNA-sequencing identified JAK-STAT signaling pathway in TSLP-activated B cells and it was verified by western blot. Anti-TSLP therapy alleviated the inflammation of lung in Lat mice. CONCLUSION: Elevated TSLP in IgG4-RD promoted B cells proliferation and polarized Tfh cells and might be served as a potential therapeutic target.

The role of PD-1/PD-Ls in the pathogenesis of IgG4-related disease.

OBJECTIVE: To investigate the role of programmed cell death protein 1 (PD-1) and its two ligands, PD-L1 and PD-L2, in the pathogenesis of IgG4-related disease (IgG4-RD). METHODS: Patients with IgG4-RD (n = 43) and healthy controls (n = 34) were recruited. Expression levels of PD-1, PD-L1 and PD-L2 in plasma, submandibular gland and T cell subsets were determined by ELISA, immunohistochemistry and flow cytometry. Naïve T cells were stimulated with or without PD-L1/PD-L2 or anti-PD-L1/anti-PD-L2 for 7 days and the proportion of CD4+CD25+ Treg cells was detected by flow cytometry. RESULTS: The expression of PD-1, PD-L1 and PD-L2 in the plasma, submandibular gland and on the surface of Treg cells was increased in IgG4-RD patients. Plasma soluble (s)PD-1 was positively correlated with serum IgG, IgG1, IgG3, IgG4, IgG4-RD responder index and numbers of organs involved, and negatively correlated with serum IgM, IgA, C3 and C4. Plasma sPD-L2 was positively correlated with serum IgG1, and plasma sPD-L1 was positively correlated with sPD-L2 and negatively correlated with C3. Stimulation of PD-L1 but not PD-L2 promoted the differentiation of naïve T cells from IgG4-RD patients into CD4+CD25+ Treg cells. CONCLUSION: Plasma concentrations of sPD-1, sPD-L1 and sPD-L2 were significantly increased in patients with IgG4-RD, and the expression of PD-1 and PD-L2 on Treg cells was upregulated. PD-1-PD-L1 can promote the differentiation of naïve T cells into Treg cells and thus participate in the pathogenesis of IgG4-RD.

Phenotype, function and clinical significance of innate lymphoid cells in immunoglobulin G4-related disease.

OBJECTIVES: The innate immune system participates in immunoglobulin G4-related disease (IgG4-RD). While the role of innate lymphoid cells (ILCs) in IgG4-RD remains to be elucidated, we aimed to evaluate the phenotype, function and clinical significance of ILCs in IgG4-RD patients. METHODS: Sixty-seven untreated IgG4-RD patients and 44 age- and sex-matched healthy controls (HCs) were enrolled. Circulating and tissue infiltration of ILCs were detected by flow cytometry. Serum suppression of tumorigenicity 2 (sST2) was detected by ELISA and membrane-bound ST2 (ST2L) was detected by flow cytometry. Tissue infiltration of IL-33 was measured by immunohistochemistry staining. Real-time quantitative PCR was performed to analyse the expression pattern of ILC2-associated genes between HCs and IgG4-RD patients. In addition, correlation analysis was performed in order to evaluate the clinical significance of ILCs in IgG4-RD. RESULTS: The frequency of circulating pan ILCs in IgG4-RD patients was lower than in HCs. ILC2s were higher in IgG4-RD compared with HCs, whereas ILC1s were lower in IgG4-RD. sST2 and ST2L were higher in IgG4-RD than in HCs. Infiltration of ILC1s in the submandibular glands of IgG4-RD patients was more prominent than ILC2s. Intracellular secretion of IL-9 was increased in ILC2s of IgG4-RD patients than in HCs. Circulating ILC2s correlated positively with Treg cells and the surface expression of CD154, PD-1 and CXCR5 in ILC2s correlated positively with CD19+ B cells, serum IgG4 levels and serum IgE, respectively. CONCLUSION: ILCs and their subsets were significantly altered in IgG4-RD. We demonstrated the dysfunction of ILC2s in IgG4-RD by phenotype, correlation analysis and function investigation, revealing ILC2s participated in the pathogenesis of IgG4-RD.

Spectrum of Spondyloarthritis Among Chinese Populations.

PURPOSE OF REVIEW: This review aims to emphasize interesting and important new findings with a focus on the spectrum of spondyloarthritis (SpA) in China. RECENT FINDINGS: Over the past decade, significant advances have been made in the investigation of SpA epidemiology, the exploration of genetic and environmental risk factors, the identification of clinical features, and the updating of treatment protocols in the Chinese population. The prevalence of ankylosing spondylitis (AS) in China is 0.20-0.42%, and the prevalence of HLA-B27 in AS patients is 88.8-89.4%. HLA-B*2704 is the most common subtype in Chinese AS patients, followed by HLA-B*2705. HLA-A*01, more precisely HLA-A*01:01, may be associated with psoriatic arthritis (PsA). Tumor necrosis factor inhibitors and IL-17A inhibitors have been shown to be effective and safe for AS patients in China. Juvenile-onset AS is relatively rare, accounting for only 9.1% of the AS population. The prevalence of arthritis related to inflammatory bowel disease is 6.9 to 7.2%. A Chinese study showed that the most frequently prescribed medication was methotrexate (66.4%). Biological agents were prescribed in only16.4% of patients with PsA. This review summarizes the latest research in the epidemiology, pathogenesis, clinical manifestations, and management of SpA among Chinese populations. Multiple HLA associations with SpA have also been described, and it is hoped that discoveries of such ethnic-specific risk factor(s) and understanding of their pathological mechanisms may potentially lead to newer targeted therapies for the Chinese populations worldwide.

Proteomic analyses of plasma-derived exosomes in immunoglobulin (Ig) G4-related disease and their potential roles in B cell differentiation and tissue damage.

OBJECTIVE: To investigate the proteomic profiles of plasma exosomes isolated from patients with immunoglobulin (Ig) G4-related disease (IgG4-RD) and to determine their potential roles in B cell differentiation and tissue damage. METHODS: One hundred untreated IgG4-RD patients and 135 sex- and age-matched healthy controls (HCs) were enrolled in this study. A combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and tandem mass tag (TMT)-label quantitation was used for proteomic profiling. Differentially expressed proteins were validated by Western blot, enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR) analyses. B cell activation, apoptosis, differentiation and reactive oxygen species (ROS) production were analyzed by flow cytometry. We also analyzed the correlations between differentially expressed complement proteins and laboratory parameters. RESULTS: A total of 178 differentially expressed proteins were identified in plasma exosomes in IgG4-RD patients compared with HCs, and these proteins were enriched predominantly in the complement cascade pathway. Furthermore, reduced expression levels of complement components C3 and C5 in IgG4-RD were correlated with clinical parameters. Following stimulation with IgG4-RD plasma exosomes, the percentages of naïve B cells decreased, while those of memory B cells and plasmablasts increased; the levels of cytochrome c, somatic (CYCS) and downstream complement system activation also increased. Moreover, ROS production was greater in B cells of IgG4-RD patients than in those of HCs. In affected submandibular glands, the BCR signalling pathway was activated, and exosomes were enriched. CONCLUSION: Proteomic profiling revealed that plasma exosome proteins may participate in the pathogenesis of IgG4-RD through complement activation and may be involved in B cell differentiation and activation of the B cell auto-oxidative damage pathway.

Differences in clinical characteristics of IgG4-related disease across age groups: a prospective study of 737 patients.

OBJECTIVE: The aim of this study was to compare the clinical characteristics of IgG4-related disease (IgG4-RD) among different age groups. METHODS: We conducted a prospective study of 737 patients who were newly diagnosed with IgG4-RD and compared detailed demographic features, organ involvements, laboratory tests, treatments and outcomes across age groups. The patients were divided into five groups according to their age at diagnosis: ≤39, 40-49, 50-59, 60-69 and ≥70 years. The clinical characteristics of paediatric patients were also described. RESULTS: Sex ratio, disease duration, allergy history and clinical symptoms were significantly different across age groups. Besides, the proportions of superficial organ involvement (lacrimal gland and sinus) decreased with age, while the proportions of internal organ involvement (pancreas, biliary tract, retroperitoneal tissue, lung and prostate) increased with age, which was more prominent in male patients. Mikulicz's disease was the most common manifestation (70%) in paediatric IgG4-RD patients. Multiple Cox analysis identified that age ≤56 years at diagnosis was an independent risk factor of relapse. CONCLUSION: We revealed the impact of age on clinical characteristics of IgG4-RD, which indicated that different management might be required among different age groups.

UPLC-MS based plasma metabolomics and lipidomics reveal alterations associated with IgG4-related disease.

OBJECTIVE: The pathogenesis of IgG4-related disease (IgG4-RD) remains unclear. Metabolomic profiling of IgG4-RD patients offers an opportunity to identify novel pathophysiological targets and biomarkers. This study aims to identify potential plasma biomarkers associated with IgG4-RD. METHODS: Thirty newly diagnosed IgG4-RD patients, age-matched healthy controls and post-treated IgG4-RD patients were enrolled. Patients' clinical data, laboratory parameters and plasma were collected. Plasma was measured for ultraperformance liquid chromatography-tandem mass spectrometry based metabolomics and lipidomics profiling. Multivariate and univariate statistical analyses were conducted to identify potential biomarkers. The receiver operating characteristic and the correlations between biomarkers and clinical parameters were investigated. RESULTS: The plasma metabolites are altered among healthy controls, newly diagnosed IgG4-RD and post-treated IgG4-RD groups. Of the identified features, eight metabolites were significantly perturbed in the IgG4-RD group, including glyceric acid 1,3-biphosphate (1,3-BPG), uridine triphosphate (UTP), uridine diphosphate glucose (UDP-Glc) or uridine diphosphate galactose (UDP-Gal), lysophospholipids, linoleic acid derivatives and ceramides. Receiver operating characteristic analysis indicated that UTP, UDP-Glc/UDP-Gal and LysoPC (18:1) had high sensitivity and specificity in diagnosis of IgG4-RD. A Pearson correlation analysis showed that 1,3-BPG and UTP were strongly correlated with clinical parameters. CONCLUSION: IgG4-RD patients have a unique plasma metabolomic profile compared with healthy controls. Our study suggested that metabolomic profiling may provide important insights into pathophysiology and testable biomarkers for diagnosis of IgG4-RD.

Ophthalmic involvement disparities in clinical characteristics of IgG4-related disease: a retrospective study of 573 patients.

PURPOSE: To investigate the clinical manifestations of orbital involvement in a large cohort of Chinese patients with IgG4-related disease (IgG4-RD). METHODS: A total of 573 patients with IgG4-related disease were included. We described and compared the demographic, clinical, laboratory and histopathologic findings from 314 patients with IgG4-related ophthalmic disease (IgG4-ROD) and 259 with extra-ophthalmic IgG4-RD. RESULTS: Male predominance was found significant in extra-ophthalmic IgG4-RD only. Patients with IgG4-ROD showed younger age at diagnosis and longer duration from onset till diagnosis. In patients with extra-ophthalmic IgG4-RD, the most commonly involved extra-ophthalmic organ was pancreas; while in IgG4-ROD patients, salivary gland was most frequently affected. Multivariate analysis exhibited IgG4-ROD was associated with allergy history, higher serum IgG4/IgG ratio, multiple organs involvement and sialoadenitis. Orbital images were reviewed in 173 (55.1%) IgG4-ROD patients. Fifty-one (29.5%) patients had multiple lesions. Lacrimal gland involvement was detected in 151 (87.3%) patients, followed by extraocular muscles (40, 23.1%), other orbital soft tissue (40, 23.1%) and trigeminal nerve (8, 4.6%). Biopsy was performed from various organs in 390 cases. A dense lymphoplasmacytic infiltration and fibrosis were the main feature in orbital specimens. Storiform fibrosis and obliterative phlebitis were absent in lacrimal gland. CONCLUSIONS: Lacrimal gland involvement was the most common orbital manifestation of IgG4-ROD. Patients with IgG4-ROD showed different characteristic in demographic, clinical, laboratory findings compared to patients with extra-ophthalmic IgG4-RD. These features might indicate potential differences in the pathogenesis of these two subgroups of IgG4-RD.

Current state of technologies and recognition of anti-SSA/Ro antibodies in China: A multi-center study.

BACKGROUND: Previous studies have demonstrated that Ro60 and Ro52 have different clinical implications, and anti-Ro52 antibodies are an independent serum marker of systemic autoimmune diseases, including Sjögren's syndrome. Many different assays have been adopted to detect anti-Sjögren's syndrome antigen A (SSA)/Ro antibodies, while to date no specific approach has been recommended as optimal for anti-SSA/Ro antibody testing. Herein, we performed a multi-center study to explore the current clinical utility of different strategies for anti-SSA/Ro antibody testing in China. METHODS: Twenty-one tertiary care centers were included in this questionnaire-based study. The self-administered questionnaire mainly includes testing methods for anti-SSA/Ro antibodies, reporting system of results, and interpretation of results by clinicians. RESULTS: Six different methods were applied to detect anti-SSA/Ro antibodies in the 21 centers. Line immunoassay (eight different commercial kits) was the most frequently adopted method (21/21, 100%), with different cutoff values and strategies for intensity stratification. There were two reporting systems: One was reported as "anti-SSA antibodies" and "anti-Ro52 antibodies" (12/21, 57%), while the other was "anti-SSA/Ro60 antibodies" and "anti-SSA/Ro52 antibodies" (9/21, 43%). Notably, six centers (29%) considered either positive anti-Ro60 or anti-Ro52 antibodies as positive anti-SSA antibodies, all of which adopted the latter reporting system. CONCLUSION: Significant variabilities existed among anti-SSA/Ro assays. Nearly 30% of centers misinterpreted the definition of positive anti-SSA antibodies, which may be attributed to the confusing reporting systems of line immunoassay. Therefore, we advocate standardization of the nomenclature of anti-SSA/Ro antibodies, changing the "anti-SSA/Ro52" label in favor of the "anti-Ro52" antibodies for a clear designation.

Alteration of CD226/TIGIT immune checkpoint on T cells in the pathogenesis of primary Sjögren's syndrome.

OBJECTIVES: Hyperactivity of T lymphocytes might play an important role in the pathogenesis of primary Sjögren's syndrome (pSS). CD226/T cell immunoglobulin and ITIM domain (TIGIT) pathway is a newly identified immune checkpoint involved in the pathogenesis of cancer and rheumatic diseases. However, its role in the pathophysiology of pSS is obscure. Hence, this study aimed to explore the potential role of CD226/TIGIT expression on T cells in the pathogenesis of pSS. METHODS: In patients with pSS, other rheumatic disease controls (DCs), and healthy controls (HCs), the expression of CD226 and TIGIT on T cells along with their activity following stimulation were detected by flow cytometry. The correlations between the expression of CD226 and TIGIT on T cells and clinical data were analyzed. RESULTS: The frequencies of CD226/TIGIT expressing CD4+ and CD8+ T cells were significantly higher in patients with pSS than in HCs and DCs. Among them, the TIGIT/CD226 expressing CD4+ T cells closely correlated with pSS disease activity: the percentages of CD4+CD226+ and CD4+TIGIT+ T cells were significantly higher in the active pSS than the inactive pSS. The proportion of CD4+TIGIT+ T cells positively correlated with the erythrocyte sedimentation rate. Further in vitro analysis revealed that CD4+CD226+ T cells exerted superior effector function than the CD226- counterparts in both pSS and HCs. TIGIT was preferably expressed on activated cells, and the activity of CD4+TIGIT+ T cells was comparable with CD4+TIGIT- T cells in HCs. However, in pSS, CD4+TIGIT+ T cells showed enhanced activity than the CD4+ TIGIT- T cells. CONCLUSION: CD226/TIGIT checkpoint molecules were over-expressed on T cells in pSS. Proportional and functional alteration of CD226/TIGIT expressing CD4+ T cells may be involved in the pathogenesis of pSS, and be a potential novel therapeutic target for the disease.

Metagenomic profiling of the pro-inflammatory gut microbiota in ankylosing spondylitis.

OBJECTIVE: Gut dysbiosis has been reported implicated in ankylosing spondylitis (AS), a common chronic inflammatory disease mainly affects sacroiliac joints and spine. Utilizing deep sequencing on the feces of untreated AS patients, our study aimed at providing an in-depth understanding of AS gut microbiota. METHODS: We analyzed the fecal metagenome of 85 untreated AS patients and 62 healthy controls by metagenomic shotgun sequencing, and 23 post-treatment feces of those AS patients were collected for comparison. Comparative analyses among different cohorts including AS, rheumatoid arthritis and Behcet's disease were performed to uncover some common signatures related to inflammatory arthritis. Molecular mimicry of a microbial peptide was also demonstrated by ELISpot assay. RESULTS: We identified AS-enriched species including Bacteroides coprophilus, Parabacteroides distasonis, Eubacterium siraeum, Acidaminococcus fermentans and Prevotella copri. Pathway analysis revealed increased oxidative phosphorylation, lipopolysaccharide biosynthesis and glycosaminoglycan degradation in AS gut microbiota. Microbial signatures of AS gut selected by random forest model showed high distinguishing accuracy. Some common signatures related to autoimmunity, such as Bacteroides fragilis and type III secretion system (T3SS), were also found. Finally, in vitro experiments demonstrated an increased amount of IFN-γ producing cells triggered by a bacterial peptide of AS-enriched species, mimicking type II collagen. CONCLUSIONS: These findings collectively indicate that gut microbiota was perturbed in untreated AS patients with diagnostic potential, and some AS-enriched species might be triggers of autoimmunity by molecular mimicry. Additionally, different inflammatory arthritis shared some common microbial signatures.

IgG4-related fibrosing mediastinitis: clinical presentation, treatment efficacy and comparison with IgG4-RD without fibrosing mediastinitis.

OBJECTIVES: This study aimed to investigate the clinical characteristics and treatment efficacy of immunoglobulin G4 (IgG4)-related fibrosing mediastinitis (IgG4-RFM) and to compare IgG4-RFM patients with IgG4-related disease (IgG4-RD) patients without fibrosing mediastinitis (FM). METHODS: Twenty IgG4-RFM patients and 60 randomly matched IgG4-RD patients without FM from a prospective cohort at the Peking Union Medical College Hospital (PUMCH) were enrolled from 2011 to 2019. Patient demographic data, clinical characteristics, laboratory parameters and treatment efficacy were analysed. RESULTS: The prevalence of IgG4-RFM in our cohort was 2.8%. The average age was 51.7±14.8 years, and the patients were predominantly male (60.0%). Periaortic masses (75.0%) and paravertebral masses (35.0%) were the most common characteristic imaging findings of IgG4-RFM. Compared with male patients with IgG4-RFM, a lower percentage of female patients had abdominal aorta involvement (p=0.015). IgG4-RFM patients had a shorter disease duration; lower percentage of allergy history, submandibular gland involvement, and pancreas involvement; lower serum IgG4; higher erythrocyte sedimentation rate (ESR) and high-sensitivity C-reactive protein (hsCRP) levels; and a higher percentage of single organ involvement than patients without FM (p<0.001, p=0.008, p=0.033, p=0.001, p=0.027, p=0.007, p=0.004 and p=0.047, respectively). After treatment, 94.7% of patients achieved a mediastinal soft tissue reduction of >30%. CONCLUSIONS: IgG4-RFM is a distinct fibrotic subtype of IgG4-RD. Periaortic masses and paravertebral masses were the most common characteristic imaging findings of IgG4-RFM. Most IgG4-RFM patients respond well to glucocorticoid (GC) and immunosuppressant treatments.